Contents  on 25 December '13

Asteroid/Comet Connection (A/CC) Resources:

The latest A/CC news is available via framed access, RSS news feed RSS news feed, or redirection. - Note: A/CC has a main Web site and also a backup site with its own duplicate RSS news feed.

Navigation tips: Use the << and >> arrows on the menus for each regular section (Observers, Risks, etc.) to move to the previous and next day's news for that section. Use the Index menu item to access specific days through a calendar interface. And use the all-up news archive to access news from any time since A/CC began in early 2002. To keep track of what's new each day, watch the Chronology section.

Traffic Report  on 25 December '13

Two objects reported inside ten LD

Two objects are reported moving inside ten lunar distances (LD) of our planet today. Risk-listed intruder 2013 YB exits Earth's Hill sphere, passing from 3.02 to 5.05 LD, and out further, 2011 YD29 is calculated with great uncertainty to be inbound from 8.2 to 7.3 LD.

This report was generated at 1536 UTC with follow-up in today's DOU MPEC for departed radar target 2013 NJ.

Notes: Ten times the distance to the Moon (ten LD) has no astronomical significance but is a useful reporting boundary. Earth's Hill sphere (of gravitational influence) is estimated to extend out to around 3.89 LD. Object distances are interpreted by A/CC from JPL Horizons data. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

NEOCP Activity  on 25 December '13

The MPC's NEO Confirmation Page has 34 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 34 objects listed. Of these, eleven were "one nighters." So far The Tracking News has counted a total of 35 listings on the NEOCP today.

To learn how observers use the NEOCP, see the Practical guide on how to observe NEOCP object at Suno Observatory by Birtwhistle et al.

New MPECs  on 25 December '13

Minor Planet Electronic Circulars

As of last check at 2359 UTC, there have been two MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

<< DOU on 25 Dec. '13 >>  MPEC 2013-Y31 - "14:02 UT" - Daily Orbit Update

MPEC 2013-Y30 - "05:31 UT" - P/2002 AR2 = 2013 Y1 (LINEAR)

Observers  on 25 December '13

Seventeen observers appear in today's MPECs.

CodeObserver / observatory
160Castelmartini Obs. in Italy, 8 in MPEC 2013-Y31 -- 2009 XZ1, 2008 TQ2, 2006 CT, 378610, 363305, 279744, 262623, 249595
703Catalina Sky Survey (CSS) in Arizona, 4 in MPEC 2013-Y31 -- 2013 XV8, 2010 SL13, 2006 CT, 88213
448Desert Moon Obs. in New Mexico, 1 in MPEC 2013-Y31 -- 2004 AS1
C15ISON-Ussuriysk Obs. in Russia, 1 in MPEC 2013-Y31 -- 2010 SL13
C41MASTER-II Obs. Kislovodsk in Russia, 1 in MPEC 2013-Y31 -- 376707
5682David Tholen's team on Mauna Kea in Hawaii, 1 in MPEC 2013-Y31 -- 2013 WR67
711McDonald Obs. in Texas, 4 in MPEC 2013-Y31 -- 2013 UC1, 2009 FF19, 2008 SO, 2004 AS1
G96Mt. Lemmon Survey (MLS) in Arizona, 10 in MPECs 2013-Y30 & 2013-Y31 -- 2013 YF, P/2013 Y1, 2013 VY13, 2011 CQ4, 2002 XS40, 1998 SZ14, 163692, 144411, 143404, 9950
J43Oukaimeden Obs. in Morocco, 1 in MPEC 2013-Y31 -- 16834
I41Palomar Transient Factory in southern California, 1 in MPEC 2013-Y31 -- 2005 RQ6
F51Pan-STARRS 1 (PS1) in Hawaii, 5 in MPEC 2013-Y31 -- 87024, 250697, 219071, 143678, 10165
H45Petit Jean Mtn. South Obs. (PJMSO) in Arkansas, 6 in MPEC 2013-Y31 -- 2013 XZ21, 2013 XV8, 2013 XA4, 2013 NJ, 2010 SL13, 52760
D29Purple Mtn. Obs. Xuyi Station in China, 3 in MPEC 2013-Y31 -- 39565, 376729, 8201
G404Don Cranford, Jr. in North Carolina via Canary Islands Obs. in the Canary Islands, 1 in MPEC 2013-Y31 -- 2013 XA4
691Spacewatch 0.9m telescope in Arizona, 4 in MPECs 2013-Y30 & 2013-Y31 -- P/2013 Y1, 2009 QD34, 96631, 154300
291Spacewatch 1.8m telescope in Arizona, 12 in MPECs 2013-Y30 & 2013-Y31 -- P/2013 Y1, 2013 XE22, 2013 WF108, 2013 UF5, 2013 UC1, 2013 TL135, 2013 TC136, 2013 RE21, 2010 SO16, 2009 KE3, 2008 VN, 2005 YY93
718Wiggins Obs. in Utah, 2 in MPEC 2013-Y31 -- 2013 XZ21, 2013 XV8
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 25 December '13

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2359 UTC)
See the CRT page for a list of all objects rated recently as risks and our ephemerides page for a list of risk-listed objects under current observation.
The time horizon for JPL is 100 years from today and for NEODyS is usually the year 2090. Both also post impact solutions beyond 100 years for a few special objects.
For the latest official risk assessments, and for explanations of the terminology, see the JPL NEO Program Sentry and NEODyS CLOMON2 risk pages.





Notes for Today's Latest Risk Assessments
2013 YCNEODyS15342031-2112241.88e-06-3.34-3.450NEODyS: "Based on 25 optical observations (of which 0 are rejected as outliers) from 2013-12-23.162 to 2013-12-24.258."

Legend: VI# = VI count, Prob Cum = cumulative probability, PS Cum/Max = cumulative/maximum Palermo Scale, TS = Torino Scale

An impact solution, also known as a "virtual impactor" (VI), is not a prediction but rather a possibility derived from a variant orbit calculation that cannot be eliminated yet based on the existing data. Elimination can come quickly with just a little further observation or may take weeks or months, sometimes years. Once superceded or eliminated, a former impact solution has zero relevance to an object's risk. See Jon Giorgini's "Understanding Risk Pages" to learn more.

Chronology  on 25 December '13

Times are UTC for when items were noted or added by The Tracking News.

1536Generated Traffic Report
1534Noted that NEODyS has posted 2013 YC as an impact risk - see above
Grabbed MPEC 2013-Y30 - P/2002 AR2 = 2013 Y1 (LINEAR) - see above
Grabbed MPEC 2013-Y31 - Daily Orbit Update - see above